Water brake



Dec. 20, 1955 J. A. GANSTER, JR 2,727,594

WATER BRAKE Filed May 11, 1953 4 Sheets-Sheet 1 Fi /gin Dec. 20, 1955 .JA, GANSTER, JR 2,727,594

WATER BRAKE Filed May 11, 1953 4 Sheets-Sheet 2 1955 JJA. GANSTER, JR2,727,594

WATER BRAKE Filed May 11, 1953 4 Sheets-Sheet 3 Joke 9% A 6am eIjJn 1955J. A. GANSTER, JR 2,727,594

WATER BRAKE Filed May 11, 1953 4 Shee ts-Sheet 4 1N1 'ENTOR.

Jake 0AA. ansdg lr ATTORNEYS,

United States Patent WATER BRAKE Joseph A. Ganster, Jr., Bryn Mawr, Pa.,assignor to Industrial Engineering Company, Philadelphia, Pa., :1partnership composed of Joseph A. Ganster, Joseph A. Ganster, Jr., EmilyLouise Ganst er and Julia A. Ganster Application May 11, 1953, SerialNo. 354,296

3 Claims. (Cl. 188-30) The present invention relates to water brakes ofthe type which are used for load tests on rotating machinery such asengines, motors and the like.

A purpose of the invention isto obtain more reliable and uniformoperation of a water brake under relatively low loads.

A further purpose is to reduce vibration and decrease the likelihood offatigue failure in a water brake.

A further purpose is to provide auxiliary longitudinally communicatingslots at the periphery of the stator plates of a water brake.

A further purpose is to permit the alternative use of the auxiliaryslots as key slots so that when wear occurs at the key slots the statorplates can be angularly shifted and reused.

A further purpose is to improve the hydraulic flow around the stator keyof a water brake.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate one only of the numerousembodiments in which my invention may appear selecting the form shownfrom the standpoints of convenience in illustration, satisfactoryoperation and clear demonstration of the principles involved.

Figure 1 is a longitudinal section of the water brake of the invention,the section being staggered and taken on the line 1-1 of Figure 2.

Figure 2 is a left end elevation of Figure 1.

Figure 3 is a right end elevation of Figure 1.

Figure 4 is a transverse section of Figure 1 on the line 44.

Figure 5 is a transverse section of Figure 1 on the line 5-5.

Figure 6 is a transverse section of Figure 1 on the line 66 omitting therotor.

Figure 7 is a fragmentary transverse section of Figure 1 on the line 77.

Describing in illustration but not in limitation and referring to thedrawings:

In the prior art brake tests on rotating equipment were commonly made ona belt type or Prony brake having a spring balance to measure the force.In recent years, extensive use has been made of a water brake, whichconsumes the energy in frictional heating of the water and determinesthe horsepower by the heat equivalent, since one horsepower is equal to42.42 B. t. u. per minute.

When reference herein is made to a water brake it is intended to adoptthe commercial terminology, and to designate a fluid brake in whichwater is usually the medium, although the medium may equally well be oilor any other liquid.

Water brakes have generally given good service and are becoming morepopular because they are reliable, simple and compact. As water brakeshave been subjected to'more extensive use, however, it has been observedthat marked tendencies exist to abrade or wear the metallic parts due tothe powerful hydraulic forces developed. This tendency has been found tobe pro- 2,727,594 Patented Dec. 20, 1955 nounced on the stator platekeys, which have heretofore been of rectangular section extendingradially inwardly from the housing. The wear is not only objectionablebecause of the need of replacing the keys, but particularly because thekey slots of the stator plates have also worn, so that after extensiveuse, there has been appreciable circumferential freedom of the statorplates in the housing. Where the load is intermittent, as in certainengines, this has caused the stator plates to jump, imparting seriousvibration which is harmful not only to the brake but to the equipmentbeing tested. Accordingly it has been necessary to replace stator platesfor this cause.

I have discovered that this difliculty can be overcome by providing aseries of alternate key slots in the stator plates, so that when wearoccurs in the key slots the device can be disassembled and the statorplates turned circumferentially and held using dilferent key slots, andemploying the same keys or new keys as desired.

I have further discovered that the Wear on the keys and key slots can bereduced by providing a deflecting surface on the key in the directionmotion of the water. Thus the tendency to damage the key and the keyslots has been markedly reduced.

In water brakes in the prior art there has been a tendency towardabnormal behavior under low loads. Even under very low loads, the wateris thrown to the outside, and there is very considerable drag exerted bythe water passing around the long circumferential path adjoining theinner wall of the housing. It has been difiicult to get sufiicient flowthrough the device to prevent generation of steam under theseconditions. I find that the slots at the periphery which are capable ofserving as alternate key slots aid in avoiding boiling of the waterunder low load since adequate longitudinal flow can be obtained underthese conditions and thus erratic or inaccurate operation is avoided.

I further find that the clearance, of the order of at least 0.015 inchon a side, between the discs and the housing, plus the slots, aids inproviding a cushion of water around the discs, thrown out by thecentrifugal force, and reducing vibration.

The water brake of the invention comprises a housing 20 consisting of atubular drum element 21 and end closures 22 and 23. The drum element 21has an annular recess at 24 which receives a reduced end portion 25 ofthe end closure having an annular slot 26 in which a sealing O ring 27of rubber or the like is placed. The drum element 21 has lugs 28 atspaced circumferential positions which support studs 30 extendinglongitudinally through stud openings in projections 31 from theendclosures, the end closures being held in place by nuts 32.

. Each of the end closures mounts a bearing 33 or 34,

Bearing 34 isheld by a retainer 41 secured to the end closure by screws42 and registered by a pin 43.

The bearings journal a main rotor shaft 44, which mounts the rotor ofthe brake.

The shaft at the left end in Figure 1 is splined at 45 to interconnectwith the shaft of the machine under test, and is threaded to receive nut46 acting against cushion washer 47 to hold inner race 48 of the bearing34 against shoulder 50 on the shaft. At the other end the shaft isthreaded to receive nut 51 acting against cushion washer 52 to holdinner race 53 of bearing 33 against shoulder 54 on the shaft.

Inside the bearings at the two ends of the housing seals and 56 aremounted in recesses in the end cloure, having external grooves forrubber 0 rings 57, 58, 60 and 61 and held by radially extending screws62. The seals have labyrinth grooves 63, 64, 65 and 66 which are inclose proximity to cylindrical shaft portions 67 and 68 respectively.

Intermediate between the labyrinth sealing surfaces are grooves 70 whichare connected by passages 71 to pipes 72 through which grease may beinjected into the seals.

The rotor comprises rotor plates 73 which have central openings 74through which the shaft 44 passes and have key slots 75 which cooperatewith a key slot 76 to receive a longitudinal key 77 extending throughthe mid portion of the shaft. The rotor plates are spaced by spacerrings 78 and the stack of spacer rings and rotor plates are locked inposition by nut 80 threaded on the shaft and acting against cushion ring81 to secure the stack of rotor plates and spacer rings against shoulder82 on the shaft. The rotor plates are perforated, there being preferablya group of perforations 83 located relatively radially inwardly and aset of larger perforations 84 near the outer edge.

In between each pair of rotor plates is placed a stator plate 85 whichis provided with an enlarged opening 86 toward the center providingadequate clearance at 87 for the spacer rings 78. The rotor plates 85also preferably clear at 88 from the housing at the circumference.

The rotor plates are slotted at 90 around the periphery, and certain ofthe slots, desirably located at quadrant positions, receive the radialinward projection 91 of a longitudinal key 92. The longitudinal keyextends in one of the longitudinal slots 93 in the housing (four areshown). The keys 92 are notched at 94 to engage on either side of thestator plate and hold the stator plate desirably equidistant from theadjoining rotor plates.

The stator plates have relatively smaller perforations 95 distributedaround the radial inner portion and relatively larger perforations 96near the outside.

The keys at positions intermediate between the stator plates haveinwardly converging longitudinal surfaces 97, desirably extending at anangle of between 30 and 60 degrees to the radius at the middle of thekey, and serving to deflect the water inwardly when it encounters thekey.

In addition to the slots which receive the keys, there are severalauxiliary key slots around the outside of the stator which would becapable of functioning as key slots should the key slots in use becomeworn and it be necessary to shift the stator plates angular-1y, with orwithout introduction of new keys.

Intake pipes 98 are provided in the end closure remote from mountingflange 100 by which the housing is supported and outlet connections 101are provided extending radially from the opposite end of the waterbrake. An annular recess 102 provides clearance in the end closureadjoining the inlet to equalize feed from the axially extending inletpipes.

It will be appreciated that the device of the invention can be readilyassembled and disassembled, and can very easily be repaired. Whenconstructed in accordance with the invention it is extremely sturdy andnot likely to require .much maintenance.

In operation, the device can be mounted either with the axis vertical orhorizontal, and a regulated water pressure applied on the inlet. Thewater flowing through the brake will of course vary with the load, andthe amount of flow and the temperature rise can be determined under theparticular conditions of test to give the information required.

In view of my invention and disclosure variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I therefore claim allsuch insofar as they fall within the reasonable spirit and scope of myclaims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In a water brake, a cylindrical housing, bearing support in thehousing, a rotor journalled in the bearing support in the housing andincluding a plurality of perforated axially displaced plates, perforatedstator plates interposed between the respective rotor plates and havinga plurality of slots at the periphery of the stator plates, wallsforming a longitudinal keyway in the interior of the circumferentialwall of the housing and a key extending through and engaging in thekeyway and extending through and engaging in the peripheral slots in thestator plates, at least some of the peripheral slots in the statorplates being open and permitting longitudinal communication.

2. In a water brake, a cylindrical housing, bearing support in thehousing, a rotor journalled in the bearing support in the housing andhaving perforated axially displaced rotor plates, perforated statorplates interposed between the rotor plates and extending adjacent to butnot into complete contact with the housing at the outside, the statorplates being slotted around the periphery, walls forming longitudinalkeyways in the interior of the circumferential wall of the housing andkeys extending through and engaging in the keyways, engaging in some ofthe peripheral slots of the stator plates, but leaving certain otherslots in the stator plates open.

3. In a water brake, a cylindrical housing, bearing support in thehousing, a rotor journalled in the bearing support in the housing andincluding a plurality of perforated axially displaced rotor plates,perforated stator plates interposed between the rotor plates and slottedat the periphery, walls forming a keyway in the interior of thecircumferential wall of the housing and a key extending longitudinallyof the housing, engaging the keyway and extending into the slots at theperiphery of the stator plates, the key having inwardly converging faceson opposite longitudinal sides.

References Cited in the file of this patent UNITED STATES PATENTS1,843,987 Ragan Feb. 9, 1932 2,514,137 OConnor July 4, 1950 2,661,915OConnor Dec. 8, 1953 FOREIGN PATENTS 348,386 France Apr. 11, 1905

